Lenz's Law Physics Example 3
Follow the full solution, then compare it with the other examples linked below.
Example 3
mediumA conducting ring is dropped through a region of magnetic field. As it enters the field, the induced current creates an upward force on the ring. Explain this using Lenz's law.
Solution
- 1 As the ring enters the field, the flux through it increases.
- 2 By Lenz's law, the induced current opposes the increase ā it creates a force that opposes the ring's entry into the field.
- 3 This opposition manifests as an upward magnetic force, partially counteracting gravity and slowing the ring's fall.
Answer
Lenz's law explains magnetic braking. The induced currents always oppose the motion that causes them, converting kinetic energy to electrical energy (then heat). This is used in eddy current brakes.
About Lenz's Law
The direction of an induced current is always such that it opposes the change in magnetic flux that produced it.
Learn more about Lenz's Law āMore Lenz's Law Examples
Example 1 easy
A north pole of a magnet is pushed toward a coil. According to Lenz's law, what pole does the coil's
Example 2 mediumA circular loop is in a magnetic field pointing into the page. The field strength decreases. Accordi
Example 4 hardA superconducting ring (zero resistance) is in a magnetic field of [formula]. The external field is